Transcript for Inside Final Rehearsals as 'Dancing' Stars Ready for Premiere

"Dancing with the stars" is back. A new season starts tonight. Our friend cam went behind the scenes for the exclusive look at the final rehearsals. ? Reporter: "Dancing with the stars" rehearsal revelation. Online right now, there is video footage of you telling Meryl you would like to marry her. Absolutely. Who wouldn't want to. Reporter: Returning pro Maks is here. Amy Purdy instagrammed from Russia, her paralimp ix blonz bed dal. She will have duct tape on her prosthetic legs. What does that do? My legs come off with a push of a button. A lot of the dance moves, I smack my legs together. I don't want to think about it. This is our makeshift fix. Reporter: I love it. Then there's Candace Cameron Bure already getting physical. I got this bruise on my shoulder because of my contemporary dance tonight. That is one of many. Reporter: The "Full house" star faces Danica Mckellar and Diana nyad. And this has to be like this, and the transfer. It's like a hundred details. Reporter: Cody Simpson and heart-throb James Maslow. This is nervousness. I might trip. I haven't done this kind of dance before. I'm excited. Reporter: There's a sneak peek at the actor, Billy Dee Williams who is rumored to have signed on for the next "Star wars" movie. Sean Avery worries about the wardrobe. No interest in anything with deep Vs or no sleeves. I've lost seven pounds. If nothing else, my posture will be great. Reporter: You're going to be doing "The price is right" like this. For "Good morning America," I'm Cameron Mathison, in los Angeles. Drew does look good. He does. He really does. The two-hour season premiere of "Dancing with the stars" tonight at 8:00 eastern. The first night is always

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